Ultrasonography is an imaging technique used to visualize subcutaneous structures in a subject, for example, an internal organ, an internal muscle structure, or a fetus within a uterus. When this technique is used for a general obstetric exam, a transducer is placed on the outside of the abdomen (e.g., transadominally) of a pregnant woman and emitted sound waves penetrate through the skin, the bladder, and other subcutaneous structures. Reflected sound waves are detected and images are created based on the reflected waves, for visualization of the uterus.
One medical technique where transabdominal ultrasonography is used is in vitro fertilization (IVF), which is a process of fertilization of an egg by a sperm that takes place outside a woman's body (e.g., in a laboratory) and then the fertilized egg is implanted in the uterus. IVF is used when there is abnormal sperm or when fallopian tubes are not patent. The process includes hormonally controlling the ovulatory process, removing ova from a woman's ovaries and letting sperm fertilize them in a fluid medium.
The fertilized egg (e.g., zygote) is then transferred to the patient's uterus with the intent to establish a successful pregnancy. A general method for transfer includes using a speculum, which allows a doctor to have limited direct vision into the vaginal cavity, and inserting a catheter through the cavity until it reaches the uterus. The zygote is then placed on the uterus wall via the catheter. A transabdominal ultrasound has been used to image the uterus to verify placement of the zygote implantation.
Unfortunately, the speculum and/or other structures between the abdomen surface and the uterus may attenuate the ultrasound beam and degrade image quality, making it more difficult to verify placement. Moreover, it may be difficult to visually determine the optimal target for embryo placement, known as the maximal potential (MP) point, from outside of the uterus.